THE TRAPPEAN ROCKS OF KILLARNEY. 
167 
the lamination at these points are given at E and F, from which it 
will be seen, either on the principle of attenuation or unconforma- 
bility of the layers, that the strata at E are in their natural posi¬ 
tion ; but that those at F have been overthrown to the northward. 
This section is about 200 yards in length; for the whole of Fig. 
1, the scale is about two inches to the foot; and in both cases the 
aspect is westward. 
ON THE TRAPPEAN ROCKS IN THE NEIGHBOURHOOD OF KILLARNEY. BY 
MR. FREDERICK FOOT. 
In the course of my duties on the Geological Survey in the vicinity of 
Killarney, I met with a large extent of trappean rocks, and as their 
existence in this locality is not generally known, I consider them 
well worthy of notice. The most westerly point where I observed 
these rocks was a deep and picturesque glen, situated about four 
miles and a half south-east of Killarney, called the Horse’s Glen. 
It lies between the mountains Mangerton and Stoompa. 
The form of the glen is remarkable, being that of an L reversed 
(j),—the lower limb turning towards the west instead of the east. 
In its north and south portions are situated two lakes, Lough 
Garagarry on the north, and Lough Managh on the south. The 
distance from the north end of the former to the south end of the 
latter is about one mile and a half. At the southern end of Lough 
Managh the glen turns at right angles to the west, and at the 
western extremity is another lake called Lough Errogh. The sides 
of the glen are steep and precipitous, proceeding southwards from 
Lough Garagarry. The trap rocks are seen on both sides of the 
glen, lying conformably between the beds of grit and slate, which are 
at the top and bottom of the cliff, that is to say, they overlie the beds 
at the bottom of the cliff, near the level of the lake, and are overlain 
by the beds at the top. When you first enter the glen at the west side 
of Lough Garagarry, the grits and slates appear to be nearly vertical, 
or dip south at 85°, but, proceeding southward, they roll to the south 
at low angles from 10° to 30°. Lines resembling stratification appear 
in places in the trap, conforming to the bedding of the grits and 
slates. On the west side of Lough Managh, where there are several 
